OXIDATION PHASE DIAGRAM OF SMALL ALUMINUM CLUSTERS BASED ON FIRST-PRINCIPLES CALCULATIONS

2009 ◽  
Author(s):  
Ligen Wang ◽  
Maija M. Kuklja ◽  
Mark Elert ◽  
Michael D. Furnish ◽  
William W. Anderson ◽  
...  
Keyword(s):  
Phase Diagram ◽  
First Principles ◽  
First Principles Calculations ◽  
Aluminum Clusters

scholarly journals Thermodynamic reassessment of Au-Pt-Sn system

2021 ◽  
Author(s):  
Jie-Qiong Hu ◽  
Ming Xie ◽  
Yongtai Chen ◽  
Jiheng Fang ◽  
Qiao Zhang
Keyword(s):  
Experimental Data ◽  
Phase Diagram ◽  
Phase Composition ◽  
Ternary System ◽  
First Principles ◽  
Catalytic Properties ◽  
Calphad Method ◽  
First Principles Calculations ◽  
Formation Enthalpies ◽  
Equilibrium Structures

Abstract Au-Pt-Sn alloys are a novel class of materials with promising catalytic properties. This study provides updated information on phase equilibrium structures and thermodynamics of the Au-Pt-Sn ternary system. The formation enthalpies of Au-Sn and Pt-Sn binary subsystems were predicted by first principles calculations and these values were further refined by CALPHAD method. The results obtained accurately reproduced the experimental data. The reassessed phase diagram of the Au-Pt-Sn ternary system accurately described the phase composition of several Au-Pt-Sn alloys, which is essential for further modifications of these materials.

Insights into the composition exploration of novel hydrogen storage alloys: evaluation of the Mg–Ni–Nd–H phase diagram

2017 ◽  
Vol 5 (8) ◽  
pp. 3848-3864 ◽  
Author(s):  
Qian Li ◽  
Qun Luo ◽  
Qin-Fen Gu
Keyword(s):  
Phase Diagram ◽  
Hydrogen Storage ◽  
First Principles ◽  
Quaternary System ◽  
Alloy Composition ◽  
Experimental Measurements ◽  
Processing Conditions ◽  
First Principles Calculations ◽  
Hydrogen Storage Alloys ◽  
Efficient Tool

In order to provide an efficient tool to explore alloy composition and processing conditions for Mg-based alloys with good hydriding/dehydriding (H/D) properties, investigation of the Mg–Ni–Nd–H quaternary system was carried out by experimental measurements and CALPHAD thermodynamic analysis combined with first-principles calculations.

Phase diagram ofBiFeO3/LaFeO3superlattices studied by x-ray diffraction experiments and first-principles calculations

2014 ◽  
Vol 90 (10) ◽  
Author(s):  
Gijsbert Rispens ◽  
Benedikt Ziegler ◽  
Zeila Zanolli ◽  
Jorge Íñiguez ◽  
Philippe Ghosez ◽  
...  
Keyword(s):  
Phase Diagram ◽  
First Principles ◽  
First Principles Calculations ◽  
X Ray Diffraction ◽  
X Ray

scholarly journals Coexistence of plastic and partially diffusive phases in a helium-methane compound

2020 ◽  
Vol 7 (10) ◽  
pp. 1540-1547
Author(s):  
Hao Gao ◽  
Cong Liu ◽  
Andreas Hermann ◽  
Richard J Needs ◽  
Chris J Pickard ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Phase Diagram ◽  
First Principles ◽  
Van Der Waals ◽  
Van Der Waals Interactions ◽  
First Principles Calculations ◽  
Helium Atoms ◽  
Wide Range ◽  
Pure Methane ◽  
The Universe

Abstract Helium and methane are major components of giant icy planets and are abundant in the universe. However, helium is the most inert element in the periodic table and methane is one of the most hydrophobic molecules, thus whether they can react with each other is of fundamental importance. Here, our crystal structure searches and first-principles calculations predict that a He3CH4 compound is stable over a wide range of pressures from 55 to 155 GPa and a HeCH4 compound becomes stable around 105 GPa. As nice examples of pure van der Waals crystals, the insertion of helium atoms changes the original packing of pure methane molecules and also largely hinders the polymerization of methane at higher pressures. After analyzing the diffusive properties during the melting of He3CH4 at high pressure and high temperature, in addition to a plastic methane phase, we have discovered an unusual phase which exhibits coexistence of diffusive helium and plastic methane. In addition, the range of the diffusive behavior within the helium-methane phase diagram is found to be much narrower compared to that of previously predicted helium-water compounds. This may be due to the weaker van der Waals interactions between methane molecules compared to those in helium-water compounds, and that the helium-methane compound melts more easily.

scholarly journals Understanding the reentrant superconducting phase diagram of the iron pnictide Ca4Al2O6Fe2(As1−xPx)2: First-principles calculations

2013 ◽  
Vol 87 (17) ◽  
Author(s):  
Hidetomo Usui ◽  
Katsuhiro Suzuki ◽  
Kazuhiko Kuroki ◽  
Nao Takeshita ◽  
Parasharam Maruti Shirage ◽  
...  
Keyword(s):  
Phase Diagram ◽  
First Principles ◽  
Superconducting Phase ◽  
First Principles Calculations ◽  
Iron Pnictide

Thermodynamic Analysis of the Fe-Mn-P Ternary Phase Diagram by Combining the First-Principles and CALPHAD Methods

2007 ◽  
Vol 561-565 ◽  
pp. 1899-1902 ◽  
Author(s):  
T. Tokunaga ◽  
N. Hanaya ◽  
Hiroshi Ohtani ◽  
Mitsuhiro Hasebe
Keyword(s):  
Experimental Data ◽  
Phase Diagram ◽  
Ternary System ◽  
Thermodynamic Analysis ◽  
First Principles ◽  
Binary Systems ◽  
Ternary Phase ◽  
Ternary Phase Diagram ◽  
First Principles Calculations ◽  
The Enthalpy Of Formation

A thermodynamic analysis of the Fe-Mn-P ternary system has been carried out using the CALPHAD method. Among the three binary systems relevant to this ternary phase diagram, the thermodynamic parameters of the Mn-P binary system were evaluated in this study. The enthalpy of formation of the binary phosphides obtained from our first-principles calculations was utilized in the present analysis to compensate for the lack of available experimental data. The thermodynamic descriptions of the Fe-Mn and Fe-P binary systems were taken from previous studies. The phase equilibria in the Fe-Mn-P ternary system were analysed based on the experimental data on the phase boundaries. The calculated phase diagrams are in agreement with the experimental results.

scholarly journals Characterizing modulated structures with first-principles calculations: a unified superspace scheme of ordering in mullite

2019 ◽  
Vol 75 (2) ◽  
pp. 260-272 ◽  
Author(s):  
Paul Benjamin Klar ◽  
Iñigo Etxebarria ◽  
Gotzon Madariaga
Keyword(s):  
Phase Diagram ◽  
Density Functional Theory ◽  
First Principles ◽  
Density Functional ◽  
Complex Nature ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Modulated Structures ◽  
Total Energies ◽  
The Ideal

The benefit of computational methods applying density functional theory for the description and understanding of modulated crystal structures is investigated. A method is presented which allows one to establish, improve and test superspace models including displacive and occupational modulation functions from first-principles calculations on commensurate structures. The total energies of different configurations allow one to distinguish stable and less stable structure models. The study is based on a series of geometrically optimized superstructures of mullite (Al4+2x Si2−2x O10−x ) derived from the superspace group Pbam(α0½)0ss. Despite the disordered and structurally complex nature of mullite, the calculations on ordered superstructures are very useful for determining the ideal Al/Si ordering in mullite, extracting atomic modulation functions as well as understanding the SiO2–Al2O3 phase diagram. The results are compared with experimentally established models which confirm the validity and utility of the presented method.

scholarly journals Thermodynamic modeling of the Sc-Zn system coupled with first-principles calculation

2012 ◽  
Vol 48 (1) ◽  
pp. 123-130 ◽  
Author(s):  
C. Tang ◽  
P. Zhou ◽  
D.D. Zhao ◽  
X.M. Yuan ◽  
Y. Tang ◽  
...  
Keyword(s):  
Experimental Data ◽  
Phase Diagram ◽  
Thermodynamic Modeling ◽  
First Principles ◽  
Calculated Phase Diagram ◽  
First Principles Calculation ◽  
Enthalpies Of Formation ◽  
First Principles Calculations ◽  
Self Consistent ◽  
Diagram Approach

The Sc-Zn system has been critically reviewed and assessed by means of CALPHAD (CALculation of PHAse Diagram) approach. By means of first-principles calculation, the enthalpies of formation at 0 K for the ScZn, ScZn2, Sc17Zn58, Sc3Zn17 and ScZn12 have been computed with the desire to assist thermodynamic modeling. A set of self-consistent thermodynamic parameters for the Sc-Zn system is then obtained. The calculated phase diagram and thermodynamic properties agree well with the experimental data and first-principles calculations, respectively.

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